The direct, low temperature conversion of hydrocarbons to functionalized products using novel, single site catalysts could lead to technological advances that redefine the landscape of the current materials and energy industries. Natural gas continues to represent a vast source of untapped hydrocarbons around the globe that has the potential to replace or augment petroleum as the raw material for materials and energy. Its abundance has garnered much interest in the scientific community as groups have focused on the catalytic conversion of its major component, methane, to functionalized products. The key requirements is to design new catalysts for the oxidative functionalization of methane that operate at lower temperatures and that also meet the basic requirements of selectivity, rate, and lifetime that characterize useful catalysts. Recent advances in the field of hydrocarbon CH activation have shown the potential for transition metal based coordination catalysts to meet these requirements. Described herein are recent advances in designing catalysts based on the CH activation reaction that address the basic requirements for practical systems with emphasis on the issues that have prevented promising reported systems from becoming commercially viable. (c) 2006 Elsevier B.V. All rights reserved.